GCC option "-fshared-data" doesn't work
 

I need to use shared data in a dynamic library via the "-fshared-data" gcc option.
When two process use the library, they always work with two private data, in place of one shared.
Here is an extraction of the make command lines :

(Compilation)
g++ -O0 -g3 -Wall -c -fPIC -fshared-data $(SRC)

(Link)
g++ -Wl,-soname,$(LINKERNAME) -shared -o $(REALNAME) $(OBJS) -lc

Is it a problem with other options ?

I use GNU C++ version 2.96 20000731. Or is it a problem with the compiler ?

Thank's for your help.